Circular chaser die head



Aug. 22, 1933. w 1 HOGG 1,923,265

CIRCULAR CHASER DIE HEAD Filed Aug. 5, 1931 igai Patented Aug 22, 1933 PATENT OFFICE CIRCULAR CHASER DIE HEAD William J. Hogg, Cleveland, Ohio, assignor to The National Acme Company, Cleveland, Ohio,

' a Corporation of Ohio Application August 5,

9 Claims.

This invention relates to automatic threading dies. more particularly, however, to the cutters or chasers thereof and to the means for supporting them, the present invention being an improvement on that shown and described in my contemporaneously pending application, Serial No. 459,700, filed June 7th, 1930, the primary object of the invention being to provide an improved circular chaser and supporting means therefor having improved means for holding the chaser in proper relative position on its supporting block.

A further object of the invention is the provision of an improved circular chaser for threading dies.

A further object of the invention is the provision of an improved chaser supporting block for threading dies.

In the drawing accompanying and forming a part of this specification, Fig. 1 is a front view of a chaser and its supporting block;

Fig. 2 is a cross-sectional view thereof showing the chaser and its supporting block assembled;

Fig. 3 is a cross-sectional view of the chaser;

Fig. 4 is a front view of the serrated bushings;

Fig. 5 is a cross-sectional view thereof;

Fig. 6 is a front view of the chaser supporting block; and

Fig. 7 is a cross-sectional view thereof.

Similar characters of reference indicate corresponding parts in the several views.

Before explaining in detail the present improvement and mode of operation thereof, I desire to have it understood that the invention is not limited to the details of construction and arrangement of parts which are illustrated in the accompanying drawing since the invention is capable of other embodiments, and that the phraseology which I employ is for the purpose of description and not of limitation.

In the present improvement, the circular chaser, its supporting block and the serrated bushing for positioning the chaser and assisting in the proper grinding thereof are similar in a general way to that shown and described in my contemporaneously pending application, in which the chaser has the grooves thereof cut straight and not spirally but the chaser is so set that it has all the effect of the spiral grooves without any of their disadvantages and in which the serrated bushing'is provided with two sets of serrations, one set different from the other, thus facilitating the grinding and setting of the chaser in the manner set forth in my said con- 1931. Serial No. 555,210

temporaneously pending application, to which reference is made for more detailed description of these features covered in said case.

In the present improvement, the circular chaser is designated as 2, the serrated opening thereof as 3, the chaser block as 4, its serrated opening as 5, the serrated bushing as 6, having the two sets of serrations 7 and 8, and the means for securing the chaser to the block as 9.

In the present improvement, however, thechaser block 4 is provided centrally thereof with a forwardly extending, exteriorly ground ring or annular flange or pilot 10 for the reception of a similar interiorly ground surface 11 located on the outer or rear side of the serrations 3 of the chaser 2, these two ground surfaces forming a means for properly positioning and supporting the chaser on the block.

This pilot is ground to fit closely within the chaser and this holds the chaser in place on the block while the serrated bushing holds the chaser from turning on the block, the face of the block being so ground, as set forth in my -contemporaneously pending application, that the chaser will be angular-1y set or inclined to the front face of the die body, thus permitting the thread cutting grooves in the chasers to be cut circularly straight and not spirally. The chaser is also ground on its back face in the manner set forth. in my said pending application to give the different positions to the chasers.

In the present instance, one set of serrations of the bushing 6, as the serration 7, are formed one-thirty-second of an inch apart while the smaller end of the bushing has the serrations formed one-sixty-Iourth of an inch apart, the larger serrations fitting into the chaser and the small serrations into the block. By means of this formation. of bushing, a very fine adjustment and grinding of the chaser is obtained since, by changing the position of the serrated bushing one notch one way in the block and then changing the chaser one notch the other way on the serrated bushing, a much finer adjustment of the chaser is obtained than would be the case with a bushing having but one set of serrations. For instance, x 24 U. S. chasers fora h- DR. die is 1 in diameter and the double serrated bushing has 22 serrations on the small end and 23 serrations on the large end,therefore, 4.712 the circumference of the chaser moved. as per serration on the small end of the bushing, =.214 moved back as per serration on the large end of the bushing =.205 =.009 difference in position from the origsett n Various combinations can'of course be used. From the foregoing, it will be observed that the chaser block of T-shaped formation having a land surface 12 curved circumferentially of the die but straight in the direction of the 4 depth of the die and an inclined or cam surface 13 in the rear of this? land surface, is provided with a forwardly projecting flange or pilot 10 accurately ground to fit a similar surface of the chaser and that within this pilot are located the serrations 5 and the serrations 3 of the chaser 2 are ground to fit the pilot with which serrations the serrated bushinghaving different diameters and different forms of serrations cooperates, whereby the chasers not only have a finer adjustment but are more rigidly and firmly supported and secured to the chaser block'than has heretofore been possible.

The serrated bushing is graduate as at 14 to correspond with the serrations on the small diameter of the bushing in order to assist in the proper setting of the bushing in the chaser block and the block is provided with a suitable center as at 15 for locating the bushing in proper position and it is also provided with a pin carried by the opening 16 for cooperation with the usual spring to shift the block outwardly when in the die holder.

It is to be understood that by describing in detail herein any particular form, structure or arrangement, it is not intended to limit the invention beyond the terms of the several claims or the requirements of the prior art.

Having thus explained the nature of my said invention and described a way of constructing and using the same, although without attempting to set forth all of the forms in which it may be made, or all of the modes of its use,

I claim:

1. A chaser supporting block having a forwardly projecting centrally located ring pilot formed as a part thereof, and provided with serrations on the interior thereof and constructed to fit into a chaser opening having a diameter to receive said pilot.

2. A chaser supporting block having a forwardly projecting ring ground pilot formed as a part thereof and having serrations on the interior thereof and constructed to fit into a chaser opening having a diameter to receive said pilot. 7

3. -A chaser supporting block for supporting a circular chaser and having at one end land and cam faces and provided with a forwardly projecting centrally located ring pilot formed as a part thereof and having serrations on the interior thereof and constructed to fit into a chaser opening having a diameter to receive said pilot.

4. A chaser block having a forwardly extending chaser positioning pilot' provided with interiorly 'formed serrations, a circular chaser having a serrated opening and a surface fitting the pilot, the serrations of the pilot and chaser being differently formed, and a serrated bushing having a plurality of sets of differently formed serrations co-operating with the serrations of the chaser and the pilot.

5. A chaser block and a circular chaser, each having a serrated opening and a serrated bushing for positioning the chaser on the block and having two sets of serrations, one set different from the other, said block having a forwardly projecting pilot extending into the serrated opening of the chaser block.

6. A chaser block and a chaser both having serrated openings of different diameters and a serrated bushing of different diameters fitting into said openings, said block and chaser'one having a forwardly projecting pilot extending into the other for positioning the chaser on the block.

7. A chaser block and a chaser both having serrated openings of different diameters and a serrated bushing of different diameters fitting into said openings, said block and chaser one having a forwardly projecting centrally located circular pilot extending into the other for pcsitioning the chaser on the block.

8. A chaser supporting block and a circular chaser, each having a depthwise extending serrated opening, the serrations of one opening being different from those of the other, a serrated bushing fitting into said openings, and said block and chaser having one a forwardly extending ground pilot fitting a ground surface of the other.

9. A chaser block and a circular chaser, each having a serrated opening and a serrated bushing for positioning the chaser on the block and having two sets of serrations, one set different from the other, said block having a forwardly projecting pilot extending into the serrated opening of the chaser block, the serrations of the chaser block having ground teeth for the 

